In the over-the-road trucking industry, it has been commom for truck drivers to install decorative hubcaps on the drive wheels and front wheels of tractor units. The hubcaps ordinarily used on the tractor wheels are of a dished shape, and frequently are referred to as "moons". The axle covers, or wheel faces, for these wheels are readily accessible and accordingly hubcaps can easily be fitted to these wheels. The rear wheels of a trailer adapted to be drawn by a tractor, however, present a different situation. The axle covers for such wheels are recessed far within the wheel wells themselves, rendering the attachment of hubcaps difficult. Asthetically, the hubcaps should be positioned adjacent the outer edges of the wheels, should be securely held, but should be readily removable so that access may be had to the axle covers for servicing.
Various devices have been used to connect hubcaps to wheels, and illustrative of these are the devices shown in U.S. Pat. Nos. 1,979,895, 3,092,420, 3,288,488, 4,123,111, 4,167,294, and 4,183,587.